- New backend/api/admin/overview.py: aggregate stats (user_count,
total_storage_bytes, doc_status) + last 10 audit entries in one payload
- Sub-router carries NO prefix (parent __init__.py carries /api/admin)
- Reuses _build_filtered_query_with_handles + _audit_to_dict_with_handles
from api.audit — no new serializer or query logic
- Registered overview_router on admin parent router in __init__.py
- All 8 ADMIN-11 tests pass; existing admin and audit suites stay green
- 8 xfail tests covering auth guards, aggregate stats, and sensitive field scan
- Tests will become real assertions once overview.py is implemented in Task 2
curo1305